§25.33 Propeller speed and pitch limits

(a) The propeller speed and pitch must be limited to values that will ensure – (1) Safe operation under normal operating conditions; and (2) Compliance with the performance requirements in CS 25.101 to 25.125. (b) There must be a propeller speed limiting means at the governor. It must limit the maximum possible governed engine speed to a value not exceeding the maximum allowable rpm. (c) The means used to limit the low pitch position of the propeller blades must be set so that the engine does not exceed 103% of the maximum allowable engine rpm or 99% of an approved maximum overspeed, whichever is greater, with – (1) The propeller blades at the low pitch limit and governor inoperative; (2) The aeroplane stationary under standard atmospheric conditions with no wind; and (3) The engines operating at the maximum take-off torque limit for turbopropeller engine-powered aeroplanes.